| 摘要 |
A bowling of synthetic material is provided. The pin has a core that is provided with pockets or cells, and also has a sheathing of solid wall construction. To achieve a particularly compact and thick outer shell, the core is also provided with an outer layer of solid wall construction that is disposed between the inner body of the core and the sheathing, and is fused with the sheathing. To provide the core with such an outer wall, the mold that receives the material that contains an expansion agent is cooled on the outside to such an extent that the expansion agent cannot become effective in the outer area.
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